This invention relates to a reflector type antenna utilized in radio communication, and more particularly a shaped beam antenna in which a radiation beam extends in a sector shape in a plane but in another shape in a plane perpendicular thereto.
In an ordinary microwave radio communication, the antenna with a pencil beam utilized to exchange communications between two radio stations aligned on a long-distance straight line is required to have a high gain and low sidelobe characteristic. However, to effect communication between a plurality of slave stations scattered in a zone and a single master station, the antenna utilized in the master station is desired to have a so-called shaped beam for efficiently irradiating the zone in which slave stations are scattered.
Although various types of shaped beam antennae have been proposed, they involve many problems to be solved, as will be described later in detail.